Lecture 1 (Louden) Flashcards
Describe polygynous vs monogamous.
Polygynous:
Intense male: male competition for females.
Evolution of weapons.
Dimorphic behaviour driven by sex steroids.
Abandonment of parental care by male.
Monogamous:
Males and females share resources.
No weapons for intrasexual conflict.
Dimorphic behaviour minimal.
Both sexes share in parental care or defence of a common family territory.
birds are weird why
The majority of bird species are monogamous
And have different sex-determining mechanisms to mammals
what led to different reproductive strategies?
difference in reproductive costs - ie heavily female orientated - pregnancy and lactation.
Males have less opportunity to share in the energy costs of rearing offspring, which has opened up selective forces for polygynous behaviour.
what has led to dimorphism in behaviour, growth and physiology?
Intense male-male competition for access to females (the limiting resource) has led to dimorphism in behaviour, growth and physiology
what drives sexual dimorphism?
sexual selection.
where is the hypothalamus located/function?
just above the brainstem.
homeostasis of hormones via control of the pituitary gland (which sits just below)
Describe the functions of the posterior pituitary gland.
oxytocin
vasopressin
both made in the hypothalamus and sent to the pituitary gland (via?)
Describe the functions of the anterior pituitary gland.
growth hormones.
FSH
LH
adrenocorticoptropic hormone
thyroid stimulating hormone
prolactin
hypothalamus connected to anteroir pituitary gland via the hypothalamic portal blood system.
what is FSH?
follicle stimulting hormone
what is LH?
luteinizing hormone
how is the hypothalamus connected to anteroir pituitary gland?
Hypothalamic portal blood system.
how is action on the gonads achieved frmo the hypothalamus?
steroidgenesis later lecture
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Specialised neurones
producing “releasing”
peptides.
Release into
Portal system
of anterior pituitary.
Large complex
glycoprotein hormones
(LH FSH) secreted to
main blood supply.
Action on gonads.
GnRH and LH FSH?
GnRH causes release of FSH and LH in pulses.
location of GnRH neurons?
Scattered through the basal forebrain (hypothalamus)
Why are GnRH neurons not active until puberty?
GnRH are connected to a variety of interneurons which are regulated by the environment.
The interneurons are not active until puberty.
secrete GnRH into portal system and reaches pituitary target cell, driving downstream LH
Gonadotrophin axis?